Method of assembling a pierce nut in a panel



April 18, 1967 P. E. DOUBLE 3,314,138

METHOD OF ASSEMBLING vA PIERCE NUT IN A PANEL Original Filed Oct. 10196] 2 Sheets-Sheet 1 37 INVENTOR.

PL mum? a. 0005, 06654560 FIG 4 'F/ 100mm LO0U5LE, AfiMl/V/STRATORflrroRNEKs April 18, 1967 5. DOUBLE 3,314138 METHOD OF ASSEMBLING APIERCE NUT IN A PANEL Original Filed Oct. 10, 1961 2 Sheets-Sheet 2 Np76 J70 18 3] 6/ f 79 7 74 so 55 74 f 752 T 5/ F/G. 7

. INVENTOR.

- 8 Ply/1411467? 5. 00054:, 0:424:50 5y non/410 L 00w; 40M/Msrmme UnitedStates Patent 2 Claims. (Cl. 29-4322) This application is a division ofcopending application Serial No. 144,132, filed October 10, 1961, nowabandoned.

The present invention relates to a method of nut-panel assembly.

In a conventional pierce nut installation, a nut having a piercing pilotportion provided with undercut grooves and a pair of laterallyprojecting flanges is displaced relative to a sheet metal panel to forcethe nut pilot portion through the panel and to bottom the nut flanges onthe panel adjacent the pilot portion. The panel is then swaged orotherwise deformed into the nut grooves to interlock the nut and thepanel against separation. Thus, the nut-pilot portion is utilized as apiercing punch, and the nut-to-panel interlock is obtained by paneldeformation into preformed grooves in the nut.

The present invention provides a novel method of making a pierce nut andpanel assembly wherein the nut not only serves as the piercing punch,but the nut is also deformed after piercing to provide the nut-to-panelinterlock. By utilizing this invention, a conventional pierce nut can bestaked at its non-grooved and nonmaking a flanged side surfaces forincreased nut-panel retention.

Alternatively, a different form of nut may be used, wherein the nut isprovided with a symmetric pilot portion (by elimination of the nutundercut grooves), the nut is deformed to substantially completelyoverlie the panel portions surrounding the nut pilot portion (to yieldan increased nut-to-panel interlock area), and the panel portionsbottomed on the. nut flange are trapped securely between contiguous nutportions (the massive nut metal being utilized to provide the interlock,rather than the relatively thin sheet metal).

Basically, the process includes the steps of positioning a sheet metalpanel in fiatwise abutment with the end face of a nut pilot portion,relatively displacing the nut and the panel with the panel in contactwith an apertured die to force the nut pilot portion through the paneland to bottom the panel on the nut flange, and then staking or otherwisedeforming the nut by its contact with the die after piercing to deforman extended portion of the nut pilot portion outwardly to overlie thepanel.

Of course, the basic process is susceptible to substantial variations.For example, the above-described process may be utilized in conjunctionwith a conventional pierce nut operation. In such an operation utilizinga polygonal nut, two or more sides of the nut pilot portion may beprovided with undercut grooves into which the metal is swaged as in aconventional pierce nut operation, while the remaining sides of a nutpilot portion are deformed outwardly to overlie the adjacent portions ofthe sheet metal. In this manner, a liquid-tight nut-panel assembly canbe obtained.

Alternatively, the nut can be provided with a groove locatedintermediate the-pilot portion and the flange and the die can beprovided with embossing surfaces for displacing into the nut groovethose portions of the sheet metal panel surrounding the pierced aperturetherein. Following formation of the embossure, the nut pilot portion canbe staked or otherwise outwardly deformed to 3,314,138 Patented Apr. 18,1967 overlie those portions of the sheet metal panel deformed into theembossure. Since the nut flange lies outside the confines of the nutgroove, the nut and the panel are in extended surface contact insurrounding relation to the panel embossment to provide an extremelyrigidly reinforced structure in which the panel is efiectively trappedby the nut completely around the panel aperture.

Another important object of this invention is the provision of a methodof making a nut panel assembly wherein a pierce nut .is deformedfollowing piercing through a sheet metal panel into extended surfaceengagement with the panel.

It is a further object of this invention to provide an improved nutpanel assembly wherein a pierce nut serves not only to pierce the panelduring assembly but also serves as the sole means retaining the nut andthe panel in assembly.

Yet another important object of this invention is the provision of aprocess for making 'a nut panel assembly by contacting the not with aforming die after a previous piercing operation to thereby deform thenut into eX- tended surface engagement with the panel.

An additional, and no less important, object of this invention is theprovision of a method of assembling a nut to a panel, the panel beingnormally planar and the nut having a pilot portion circumscribed by agroove located inwardly of an outer nut flange, by relative movement ofthe panel and the nut to force the nut pilot portion through the panelto punch an opening therein, embossing the.panel portion surrounding theopening into the nut groove and staking the peripheral edges of the nutpilot portion outwardly to overlie the groove, thereby trapping theembossed portion of the panel therein, the nut flange supporting thepanel outwardly of the panel embossment.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

On the drawings:

FIGURE 1 is a plan view, with parts broken away and in section, of a nutpanel assembly made in accordance with the present invention;

FIGURE 2 is a side elevational view of the nut and the panel prior toassembly;

FIGURE 3 is a side elevational view similar to FIG- URE 2 but taken atright angles thereto;

FIGURE 4 is a view of the assembly of FIGURE 1 taken along the plane 4-4and illustrating the forming die from which the assembly is made;

FIGURE 5 is a view similar to FIGURE 4 taken along the panel 55;

FIGURE 6 is a plan view of a different form of nut and panel taken priorto assembly; 1

FIGURE 7 is a sectional view taken along the plane 77 and alsoillustrating the forming die;

FIGURE 8 is a view similar to FIGURE 7 illustrating the nut and panelafter assembly; and

FIGURE 9 is a view of the assembly taken along the plane 99 of FIGURE 8.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of being practiced or carried out in various ways. Also,it is to be understood that the phraseology or terminology.

employed herein is for the purpose of description and not of limitation.I

As shown on the drawings: In FIGURE 1, reference numeral 10 refersgenerally to a nut and panel assembly of the present invention, thisassembly consisting of an essentially planar sheet metal panel 11 and anut indicated generally at 12.

As best illustrated in FIGURES 2 and 3, the nut 12 consists of agenerally rectangular body 13 having an upper surface 14 constituting abottoming flange located generally beneath a pilot portion 15. Thispilot portion 15 is also generally rectangular, two opposing verticalside surfaces of the pilot portion having undercut grooves 16 therein(FIGURE 2) and the other vertical side surfaces 17 of said pilot portionbeing truly planar in configuration and lying perpendicularly to theplane of the flange surface 14. It will be noted that the sides 17- arenot grooved and are not flanged.

The nut is provided with a central threaded aperture 18 opening from thebottom face 19 of the nut onto the upper piercing face 20 thereof.Further, the nut is provided with sharp, right-angular cutting edges 21defined at the extremities of the upper pilot portion face 20 by theirintersection with the side walls of the nut pilot portion.

The method of forming the nut panel assembly 10 is well illustrated by acomparison of FIGURES 4 and wherein there is illustrated a forming die25 having a central, axially extending aperture 26 of substantially thesize and contour of the nut pilot portion 15. The lower or active face27 of the die 25 includes an outer planar peripheral portion extendingcompletely around the lower face of the die.

As shown in FIGURE 2, those edges of this lower face 27 of the diealigned with the recessed faces of the nut 12 are provided with lowercutting edges 28 defined intermediate downwardly and inwardly slopingdie faces 29 and downwardly and outwardly sloping die faces 30.

From FIGURE 3, it will be seen that those portions of the die face 27aligned with the planar side walls 17 of the nut 12 are provided with alower relatively planar surface 31 merging into the planar outer diesurface 27 through upwardly and outwardly inclined faces 32. The innerextremity of the surface 31 is defined by an upwardly and inwardlyinclined face 33 terminating at an upper corner 34 displaced verticallyabove the lower die surface 27. I From this corner 37, a staking surface35 is inclined inwardly and downwardly for juncture with the dieaperture 26 in a sharp, acutely angled shearing edge In the formation ofthe nut panel assembly the panel 11 is superimposed upon or otherwisecontacted with the upper surface 20 of the nut pilot portion, and thenut 12 and the panel 11 are displaced relatively to one another with thepanel 11 in contact with the forming face of the die 25. Asschematically illustrated in FIGURES 4 and 5, the nut is disposed onsupport surface 37. Actually, the nut and the panel are initiallyjointly displaced relative to the die, either by advancing the nut 12and the panel 11 in contact therewith as illustrated in FIGURE 2 of thedrawings into contact with the die or by moving the die into contactwith the panel as supported on the nut. Alternatively, the panel can beplaced in contact with the die and the nut then displaced into contactwith the panel.

The first operation consists in moving the panel 11 relative to the nut12 to punch the nut pilot portion 15 through the metal to form anaperture in the panel 11 and to bottom the panel 11 on the flange 14 ofthe nut. That portion of the panel punched therefrom to form thepilot-receiving aperture enters the die bore 26 and does not interferewith subsequent processing.

Continued relative movement of the nut and the panel relative to the dieperforms two separate and distinct operations. One such operation isbrought about by engagement of the die surfaces 29 and 30 with the panelimmediately adjacent the panel aperture. The embossed edge 3 of the dieindents the panels and swages or otherwise deforms those portions of thepanel adjacent the aperture thereof into the undercut recesses 16 of thenut 12. The engagement of the surfaces 29 and 30 with the panel actuallydepresses the panel, as at 40, and the resultant swaging of the panelwill firmly interlock the corresponding two edges of the panels withinthe recesses 16. This is a conventional pierce nut operation.

The other operation is illustrated in FIGURE 5 of the drawings.Initially the aperture 41 is punched through the panel 11 by the nutpilot portion 15,'then depending surface 31 of the die contacts thepanel 11, in closely spaced, parallel relation to the adjacent verticalnut pilot side wall 17 to depress the panel over the nut to an extentgreater than the depression of the panel portion supported by the nutflanges 14. At the same time, the sharp, acute corner 36 of the die 25engages the adjacent edge 21 of the nut pilot portion 15, thus causingthe upper corner 21 of the straight nut side 17 to be sheared anddeformed outwardly as directed by the die surface 35. In this manner,those edges of the pilot portion 15 overlying the straight nut pilotportion sides 17 are staked or otherwise deformed outwardly from thebore 18 to overlie, as at 43, the aperture 41. The outward flow of thestaked nut metal, at 43, rounds the aperture edge, as at 42.

Thus, those portions of the sheet metal panel 11 surrounding the nutpilot portion 15 are secured in contact with the nut. Two types ofsecurement are illustrated in conjunction with that embodiment of theinvention illustrated in FIGURE 1 of the drawings. First, as illustratedin FIGURE 4 of the drawings, the metal is swaged or otherwise deformedinto the nut recesses 16 along opposing sides of the nut. Sheet metalalong the remaining sides of the nut pilot portion 15 is contacted bythe staked portion 43 of the nut pilot portion 15. Preferably, the acuteangular securing or staking edge 36 is coextensive with the entire edgeof the nut pilot portion 15, so that the entire side of the nut isdeformed, as at 43, to effect substantial surface contact between thenut and the sheet metal. An extremely strong nut-to-panel interlock isprovided, not only by the extended surface contact between the nut andthe sheet metal, but also by the engagement of the staked portion 43 ofthe nut and the sheet metal.

In that embodiment of the invention illustrated in FIG- URES 6 through9, the entire nut panel assembly operation is carried out by essentiallythe same staking technique as illustrated in FIGURE 5 and as heretoforediscussed.

More specifically, the nut 50 is rectangular in outline and includes acentrally located, rectangular pilot portion 51 having a coaxialthreaded bore 52. The pilot portion has an upper piercing surface 53terminating in a sharp shearing corner 54 overlying a straight verticalpilot side Wall surface 55. The side wall surfaces 55 cooperate with aparallel outer side surface 56 to define therebetween a groove 57 havinga planar bottom wall 58. The outer periphery of the nut 50 is defined bya planar upper sur-- face 59 defining the upper extremity of the nutflange 60..

The pilot portion 51, the groove 57 and the flange 59 are all concentricabout the axis of the bore 52. Addi-- tionally, it will be noted thatthe thickness of the pilot. portion 51, i.e., the distance from the nutplanar face 61. to the pilot portion surface 53 is greater than theflange thickness, i.e., the distance from the nut surface 61 to theflange surface 53. This difference in thickness is substantially thesame as the thickness of the sheet metal panel 65, for a purpose to behereinafter more fully described. Further, it will be noted that thebottom surface 58 of the groove 57 is below the surface of the flange 59and, of course, is below the surface 53 of the pilot portion 51.

Once again, the assembly of the panel 65 and the nut 50 is carried outby utilization of a die '70. This die 71 is rectangular in configurationand includes an outer peripheral flange surface 71. Additionally, thedie ineludes rectilinearly arranged embossing ledges 72, these ledgesbeing defined by outer surfaces 73, inner surfaces 74 and medial orembossing surfaces 75. The inner embossing surface 74 merges through anupper corner 76 with an inwardly and downwardly inclined staking surface77 terminating in an acute sharpened corner 78. This corner 78 isactually defined by the convergence of the staking surface 77 and aninner shearing surface 79. It will be appreciated that the end face ofthe die 70 in the illustrated embodiment of the invention consists offour rectilinearly arranged portions similar to that just defined, theportions being spaced and located for alignment with the four edges ofthe rectangular nut pilot portion 51. In the event that a nut pilotportion of ditferent configuration is utilized, e.g., hexagonal or evencircular, a similarly shaped die end face is provided.

In operation, the sheet metal panel 65 is superimposed on the pilotsurface 53 of the nut 50, and the panel 65, the nut 50 and the die 70are then displaced relatively from their positions of FIGURE 7. It will,of course, be appreciated that the die 70 may be displaced verticallydownwardly from its position of FIGURE 7 into contact with the sheetmetal as the sheet metal is supported on the nut or, alternatively, thesheet metal 65 may be interposed between the nut 50 and the die 70, thesheet metal being in contact with either of the other two elements, andthe nut is then advanced toward the die.

In any event, initial contact is effected between the embossing surface75 of the die and the sheet metal panel 65, the sheet metal being atleast partially embossed thereby toward the groove surface or bottom 58.Next, and before the embossing surface 75 is effective to fully embossthe panel 65, the nut pilot portion 51 is punched through the sheetmetal 65 to form an aperture in the sheet metal conforming to the sizeand shape of the nut pilot portion 51.

Continued relative nut-to-die movement with the sheet metal 65interposed therebetween results in displacement of those portions of thesheet metal surrounding the aperture into the groove 58 and engagementbetween the acute corners '78 of the die and the pilot surface 53 of thenut projecting through the sheet metal aperture. This engagement betweenthe sharpened corners 78 of the die and the surface 53 occurs inproximity to the nut pilot portion corners 54 and results in shearingand outward staking of the peripheral portions of the nut pilot portions53.

As best illustrated in FIGURE 8 of the drawings, the final configurationof the nut panel assembly includes an embossment 80 in the sheet metalsurrounding the pilot portion 51 of the nut, this embossment includingan outer vertical sheet metal wall 81 engaging the outer wall 56 of thenut recess 57, a sheet metal horizontal portion 82 bottomed in the nutrecess against the bottom wall 58 of the groove, and an upturned innerflange 83 formed in the sheet metal against the original vertical sidewall 55 Additionally, the upper surface 53 of the nut is sheared andindented by the die edge 78, as at 85, so that the outer edges 54 of thenut pilot portion 51 are staked or otherwise deformed outwardly tooverlie the nut groove 57, as at 86, and to trap the sheet metalembossment in the nut groove inwardly of the nut flange 59.

In that embodiment of the invention illustrated in FIG- URES 6 through9, substantially the entire outer periphery of the nut pilot portion isstaked or deformed outwardly to overlie the nut groove 57 encircling thenut pilot portion. In addition, the sheet metal is embossed into thegroove after the nut has pierced the sheet metal panel and after thepanel has been bottomed upon the nut flange surface 59. The resulantlater staking of the nut pilot portion traps the embossed portions ofthe panel in the nut groove 57.

What is claimed is:

1. A method of assembling a rectangular nut having a central rectangularpilot portion and outer flanges to an essentially planar panel, the nuthaving undercut recesses on two sides only of the pilot portion, byrelatively moving the nut and the panel in a single uninterrupted motionsequentially 1) piercing the panel with the nut pilot portion, (2)bottoming the panel outwardly of the recesses on the nut flanges, (3)swaging the panel portions on said two sides of the pilot portion intosaid recesses and (4) staking outwardly the remaining two sides of thenut pilot portion to overlie the remaining panel portions.

2. In a method of assembling an essentially planar plate and a nuthaving a face thereof provided with a raised central polygonal pilotportion having opposing sides provided with undercut recesses and othersides planar and of the nut pilot portion 51.

outer flanges joined to the recessed nut sides, by relatively displacingthe nut and the plate with the plate in contact with a forming die tosequentially perform the steps of (1) punching the nut pilot portionthrough the plate until the plate bottoms on the nut flange (2) swagingthese plate portions adjacent said opposing sides of the pilot portionof the nut into the nut recesses, and (3) smoothly and continuouslydeforming outwardly the upper outer edges of the planar sides of the nutpilot portion to overlie the remainder of the plate portion surroundingthe nut pilot portion.

References Cited by the Examiner UNITED STATES PATENTS 2,652,942 9/1953Muchy. 2,750,660 6/1956 Newcomb 151--41.73 X 3,229,363 1/ 1966 Bien29-432 FQREIGN PATENTS 539,221 4/1957 Canada.

CHARLIE T. MOON, Primary Examiner.

1. A METHOD OF ASSEMBLING A RECTANGULAR NUT HAVING A CENTRAL RECTANGULARPILOT PORTION AND OUTER FLANGES TO AN ESSENTIALLY PLANAR PANEL, THE NUTHAVING UNDERCUT RECESSES ON TWO SIDES ONLY OF THE PILOT PORTION, BYRELATIVELY MOVING THE NUT AND THE PANEL IN A SINGLE UNINTERRUPTED MOTIONSEQUENTIALLY (1) PIERCING THE PANEL WITH THE NUT PILOT PORTION, (2)BOTTOMING THE PANEL OUTWARDLY OF THE RECESSES ON THE NUT FLANGES, (3)SWAGING THE PANEL PORTIONS ON SAID TWO SIDES OF THE PILOT PORTION INTOSAID RECESSES AND (4) STAKING OUTWARDLY THE REMAINING TWO SIDES OF THENUT PILOT PORTION TO OVERLIE THE REMAINING PANEL PORTIONS.